Portion of a tractor



FIG. 1 is a right side view of a portion of a tractor showing our new design. The parts of the photograph shown in coarse dot pattern and outlined in dashed lines illustrate portions of the tractor that form no part of the claimed design;

FIG. 2 is a left side view thereof. The parts of the photograph shown in coarse dot pattern and outlined in dashed lines illustrate portions of the tractor that form no part of the claimed design;

FIG. 3 is a front view thereof. The parts of the photograph shown in coarse dot pattern and outlined in dashed lines illustrate portions of the tractor that form no part of the claimed design;

FIG. 4 is a reduced top plan view thereof. The parts of the photograph shown in coarse dot pattern and outlined in dashed lines illustrate portions of the tractor that form no part of the claimed design;

FIG. 5 is an enlarged right front perspective view thereof. The parts of the photograph shown in coarse dot pattern and outlined in dashed lines illustrate portions of the tractor that form no part of the claimed design;

FIG. 6 is a left front perspective view thereof. The parts of the photograph shown in coarse dot pattern and outlined in dashed lines illustrate portions of the tractor that form no part of the claimed design;

FIG. 7 is a reduced left rear perspective view thereof. The part of the photograph shown in coarse dot pattern and outlined in dashed lines illustrates a portion of the tractor that forms no part of the claimed design. The right rear perspective view is a mirror image thereof; and,

FIG. 8 is a reduced left front perspective view thereof. The parts of the photograph shown in coarse dot pattern and outlined in dashed lines illustrate portions of the tractor that form no part of the claimed design. The right front perspective view is a mirror image thereof. 

The ornamental design for a portion of a tractor, as shown and described. 